1. Alameda County Environmental Health - Vector Control
4/25/2017
David K. James, REHS
Alameda County Environmental Health - Vector Control
October 20th, 2015

2. Biology of the Human Bed Bug
Cimex lectularius
1 - Talk not on why there is a higher incidence of bedbugs - don’t know
2- Bed bugs are fascinating insects.
3 - Part of our oral traditions. Parents still tell their young children at bed time “Don’t let the bed bugs bite”.
4 - There are many misconceptions concerning bedbugs: mythical, related to the “boogie man”, tiny in size. Sexually transmitted (It’s not what you do in the bed but number of beds slept in or misidentification)
5 - Not many ectoparsites specific to humans. Part of our ecology.
6 - Could view them as Micropredators.

3. Since the mid 1990’s, Bed bugs have become more common
Bed bugs tend to be associated with poorly maintained and poor sanitary conditions, however …..
Any house is a good habitat for bed bugs. (A place to shelter and a food source is all they need)
1- Until 1940’s , bedbugs were a common human parasite. For example, in the 1930’s it was estimated that 1/3 of English households were infested.
2- It was more common then probably because pesticides and pest control was less accessible, had “lower standard of living” such as more people per household, no washing machines, conducive construction.
3 - Since then the incidence of bedbug infestations have been reduced greatly, primarily with the invention of new pesticides such as DDT and its discriminate and indiscriminate use. There was also an effort by governments to raise the standard of living of its citizens especially the working class. Post war England made an effort to clear the slums and place people in new habitations. Personal items were all fumigated prior to moving into new home. Innovations in technology such as washing machines helped as well as changes in house construction - less harborage sites i.e.. Mouldings
4- Bedbugs were and still are associated were poorer areas and poor sanitation. This is really not the case especially today. Poor tended to have heavy infestations because they are unable to do anything about it or can not afford it or have other problems such as mental disorders, physical, medical problems or are elderly and infirm. BEDBUGS DO NOT EAT DIRT SO CLEANLINESS NOT A CONDITION CONDUCIVE.
Still today: S.F. say problem in Tenderloin flop hotels but cases in “good” hotels and motels. Las Vegas hotels had a big problem.
You are asking for trouble if you tell a manager or resident that the infestation is caused by poor sanitation.
A place to stay
And something to eat

4. Service Requests ACVCSD
Tremendous increase in Bed bug calls.
Mostly multi-unit residential (both low rent and high rent), motel/hotel (low budget) and some single family.
Initially infestations found in high-end hotels in New York, Las Vegas, San Francisco (late 1990s to early 2000s)
Now spread throughout the community nationwide.

5. Bed Bug Biology some Important aspects for control
Order: Hemiptera ( Sub-Order: Heteroptera)
Family: Cimicidae (74 spp)
Genus: Cimex
Species: lectularius
Piercing and sucking mouth parts
Feeds exclusively on the blood of mammals (related species on birds).
Preferred host of C. lectularius is HUMANS – (Much preferred)
Control implications: Pesticides are NOT ingested

6. Hemiptera: True bugs Leaf-footed bug Harlequin bug Cotton strainers
Reduviidae: Triatoma spp.:Chagas disease
Examples of True bugs
Leaf-footed bug
Harlequin bug
Cotton strainers

7. Other insects & mites with human hosts
Let’s not forget that there other ectoparasites of humans.
Bird mite
Scabies mite
Tropical rat mites
Chigger

8. Family Cimicidae This family includes the parasites of animals.
These ecto-parasites feed on the blood of birds and mammals, including bats.
Bed bugs are flattened dorso-ventrally. Front wings are always reduced to small pads.
All species live away from the host animal except when feeding.
Small Family, all parasites mostly of birds and bats.
All flattened with reduced wings (wing pads)
As with other ectoparasites, not found on host, live in the nest area such as bedroom. Only on host to feed. Feed on blood
Poultry bug also called the Mexican Chicken bug.
Characters: Short broad head, broadly attached to the prothrorax, oval body, compound eyes, no occelli, 4 segmented conspicuous antennae, 3 segmented proboscis, very short pad-like hemelytra.
Relatively small family
13 genera exclusively associated with bats
9 genera exclusively associated with birds
74 species
3 species commonly attack man
Cimex lectularis - man, bats, chickens & others
Cimex hemipterus (Tropical bed bug)- man, chickens, rarely bats. Florida and tropics
Leptocimex boueti - West Africa

9. Bedbugs are flattened dorso-ventrally
Bedbugs are flattened dorso-ventrally. Front wings are always reduced to small pads.
1 - Note the oval flattened body, small wing pads, conspicuous antennae.
2 - Ideally adapted to live in tiny cracks and crevices.
3 – Move quickly

10. Related species attacking man
BAT BUG, Cimex pilosellus (Horvath)
Occasional household pest
SWALLOW BUG, Oeciacus vicarius
May enter homes when swallow nests removed
POULTRY BUG, Haematosiphon inodorus
Found in hot dry areas
Can become severe poultry pest
May invade homes
Should be aware other cimicids can bite humans.
Check for nesting birds, poultry and bats 10

11. Cimex lectularius (Linnaeus) Common Human Bed bug
Feeds primarily on humans but will attack bats, chickens and other mammals
Worldwide distribution
Ancestor probably bat parasite that utilized “cave dwelling human”
Earliest record c.1350 BC in Egypt
1 - Have been associated with humans probably since evicted from garden of Eden and had to live in caves.
2 - Commonly mentioned since recorded history. Cimex was the roman word for the bed bug. The word “Bug” probably was derived from the Arabic word for the bedbug (buk)
3 - Old World bug that was introduced to America with the early colonists.
Roman name was Cimex
Word ‘bug’ probably came from word used for the bed bug. Came from the Arabic word ‘buk’ used to describe the bed bug.
Called Red Coats, Chinches, mahogany flats
May have found another species in Oregon.

12. BED BUG LIFE CYCLE Ectoparasites Five nymphal stages and adults
Obligated blood feeders with all stages
Not implicated as a disease vector
Important aspects:
Eggs glued on surface
1st instar very small
Need blood meal to moult and egg development

13. 3. Females can lay 1-5 eggs per day. Hatch in 7-10 days
Short life cycle – days (under optimal conditions)[ 75-80% RH; 83-90o F ]
2. Eggs resistant to pesticides and heat and can be laid (glued) anywhere.
Can get a large population after one month
3. Females can lay 1-5 eggs per day Hatch in 7-10 days

14. 4. Blood meal needed to molt and for egg laying.
Only 10% of bedbugs will be feeding on a particular night
5. Most harbor near host (70%) but not all
6. Live in cracks and crevices, difficult to locate. Prefer rough surfaces
Bed bugs feed once every 10 days or so, resting & digesting during that time.

15. Can go without Feeding for some time:1.
7. Bite is painless, most people don’t react initially. Older people react less to the bite.
Population can grow quite large before resident is aware of the infestation
Can go without Feeding for some time:1.
1st instars most vulnerable (14-36 days)
5th and adults least vulnerable ( days)
If don’t react, wont know if have BB and population can grow. Mngt accuses tenant of not informing them, when didn’t know. Not experts.
9. Nymphs & adults stop feeding at 56oF (13oC)
Thermal death point is 7 hrs, 118F (ad) 123F 0 min

16. Can walk over pesticide treated area without being affected
NO tarsal pads
No pads to pick up pesticide
Tarsal pads
House fly
Implications for control
Can walk over pesticide treated area without being affected
Walk with body off the ground

17. Typical feeding position
Engorged bedbug
Typical feeding position
1 - Note feeding position
2 - Changes color after feeding and will increase in size.
3 - Humans preferred host but will feed on rats, mice, rabbits birds etc..
Bug has to grasp host with legs to feed. If remove forelegs will not be able to feed.
Blood fed bedbug will expel up to 50% of blood meal. Leaving blood/fecal spots
Feed between 12 & 6 AM
Feed for 2-15 mins. Multiple feeding sites

18. Blood/fecal spots on pillow case
Usually harbor near the host but can be some distance from host. Leave pheromone trail.
Primary reason for inspection: EXTENT OF INFESTATION
Also physical evidence for possible litigation
Initial infestation easier to control but still all possible harborage sites to be treated.
Harborage site, a short walking distance to restaurant
All stages micturate

19. male
female
1 -Some people think that bedbugs are very small but adult Bedbugs are relatively large insects.
Male & Female bedbugs next to a dime ($.10)
However nymphal bugs are quite small.

20. TRAUMATIC INSEMINATION Reproduction
Copulating couple
Unusual reproduction – extragenital.
Male punctures body wall of female to inject spermatozoa into the spermalege.
Spermatozoa migrates to female genital tract.
No courtship - mate rapidly.
Mating occurs away from host.
Females may travel some distance to get away from males.
1 - Bedbug reproduction in very interesting and I bring it up because you can impress the human host by describing extragenital or even better Traumatic Insemination.
2 - The male uses a specialized spur to pierce the female’s abdomen at the copulatory cleft then the spermatozoa migrate to the ovaries.
3 - They mate rapidly without any courtship.
4- Female will leave aggregations to get away from males. Eggs can be laid a distance from host.
5 - Can mention that mating does not occur on them.
Male mounts female on top and grasps with 2 front legs. The male paramere, a modified claw-like structure, pierces female abdomen at the spermalege. (Right side of the posterior margin of the fourth abdominal segment) Spermatozoa pass to sperm-storage organ, seminal conceptacles, then to the wall of the ovaries.
Blood meal needed first before migration occurs.
Possibly adapted due to confined harborages.

21. Male paramere Beak or rostrum Cleft of copulatory pouch (female)
The male has a pointed abdomen.
Note copulatory pouch
the male actually pierces (or stabs) the abdomen of the female with a dagger-like penis called the paramere
Male paramere

22. Meta-thoracic scent apparatus Host Detection: (when unfed)
Cimex lectularis tends to cluster in cracks, preferring old harborages and places which smell of bed bugs.
Meta-thoracic scent apparatus
Host Detection: (when unfed)
Temperature
Attraction to oily skin secretion and CO2 involved.
1 - Because attracted to “old scents”, may need to clean harborage sites as well as treating esp. in hotels etc with high occupancy turnover.
2 - Adults and nymphs produce scents used to form aggregations and trail laying as well as alarm pheromones. With large infestations, can have a characteristic odor.
3 - Bedbugs can move very quickly when alarmed. As with other insects, will “freeze” when in danger and drop to the floor.
4 - Oils produced on the host skin is the primary way host is detected however warmth and CO2 are also involved. First random then more directed. Will place scent trails. Though mechanism is still not well understood.
Nymphs scent gland upper abdomen. Adult ventral part of thorax.

23. Pesticide resistance
Resistance to pyrethroids among bed bugs has become a major problem.
A number of resistant populations have been identified on the West Coast. An increasing number of resistant bed bugs are being found especially in the East Coast
If getting control failures – consider pesticide resistance LAST
Important part of biology is capability for insecticide resistance.
Mutation change sodium pore so that pyrethroid no longer binds to it

24. Pyrethroids bind to a protein in nerves called voltage-gated sodium channel prevent it from closing, causing continuous nerve stimulation.
Resistant bed bug populations have evolved by changing the size of the pore (gate), preventing the binding of the pyrethroid.
Resistance-associated genes have been found in the integument (cuticle) of the bed bug which could reduce insecticide penetration and enhance detoxification before reaching the target sites.
Same mode of action as DDT

25. The more you know about Bed bugs…
To Conclude
The more you know about Bed bugs…
The easier it is to control (kill) them.
BB not out to get you. 90% are inactive in cryptic hiding places.
Most are around the host (bed system) and couches.
Identifying nymphs and adults early may prevent infestation at work and home.
Recognizing initial BB signs ( blood spots and bites) will reduce pest control costs.
David K. James